I'm a "newbie" here, and would like to ask for your help with a project I'm
working on for school.
I have a GMRS radio with an built-in antenna, and just for
experimentation I wanted to see how my coverage would be with an external
antenna (I do have a GMRS licence from the FCC). The integrated antenna
which is on this radio simply connects to the PC board of the radio when
you screw the outter shell of the radio together. I have a 1/4 wave
ground plane antenna tuned to the proper GMRS frequency, and I'd like to
connect it to this radio, but my question is this...When connecting an
external antenna, I will connect the inner wire from the coax to the
circuit board where the radio's original antenna was attached. However,
I'm not certain where the outter shield of the coax should be
connected..To the - side of the battery connection in this GMRS radio?
Should there be some kind of capacitor between the inner wire and outter
shield of the coax?
I'm only connecting this external antenna long enough to take some
measurements I need for this research project for school, then will return
it to normal. This isn't a long term illegal modification I'm asking you
to help me with, etc.
Thanks for your help!

Bababooey wrote:

I'm a "newbie" here, and would like to ask for your help with a project I'm
working on for school.
I have a GMRS radio with an built-in antenna, and just for
experimentation I wanted to see how my coverage would be with an external
antenna (I do have a GMRS licence from the FCC). The integrated antenna
which is on this radio simply connects to the PC board of the radio when
you screw the outter shell of the radio together. I have a 1/4 wave
ground plane antenna tuned to the proper GMRS frequency, and I'd like to
connect it to this radio, but my question is this...When connecting an
external antenna, I will connect the inner wire from the coax to the
circuit board where the radio's original antenna was attached. However,
I'm not certain where the outter shield of the coax should be
connected..To the - side of the battery connection in this GMRS radio?
Should there be some kind of capacitor between the inner wire and outter
shield of the coax?
I'm only connecting this external antenna long enough to take some
measurements I need for this research project for school, then will return
it to normal. This isn't a long term illegal modification I'm asking you
to help me with, etc.
Thanks for your help!


Being GMRS your radio follows different regulations from FRS radios,
however since the radios you are working with have attached antennas I
would assume that the type acceptance is predicated on only using the
attached antennas. If you remove these antennas and attach an external
antenna you will be in violation of the registration. Momentary
modification or not your base action will be illegal.

If you do do the mod attach the shield to the foil that goes around the
perimeter of the pc board. That is usually a ground. Check the negative
lead (black) from the battery connector. It should connect to this foil
somewhere.

Dave Nagel WD9BDZ